The Research Of Epitaxial Growth Of InSb Thin Films On Silicon-based Substrate

Among III-V compound semiconductors,InSb owns the highest electron mobility and the smallest band gap that is appealing in many technical applications.For examples,InSb-based materials are usually employed for fabricating infrared detectors,high-speed devices,and magnetic sensors.In this thesis,the integration of InSb thin films on Si(111)substrates by molecular beam epitaxy(MBE)method was explored.By using an ultra-thin Bi(001)thin film as a buffer layer,it's demonstrated that InSb films with In-polar could be achieved..A comprehensive research on the growth kinetics of InSb on Bi-buffered Si(111)surface was carried out by a conjuncted method including scanning tunneling microscope(STM),X-ray diffraction(XRD),and other technical means.The optical and electrical properties of InSb thin film were also studied.The main work accomplished in this thesis is summarized as follow.Firstly,we used MBE technology to grow Bi(001)thin films with good crystal quality and in-plane lattice matching with InSb(111)lattice(4.57?lattice constant)on Si-(7×7)surface.The Bi(001)thin film can be used as a buffer layer for growing InSb thin films,and the morphology and crystal structure of the Bi(001)thin film were characterized by STM and XRD,which provided the evidence for the subsequent growth of InSb(111)thin films.Secondly,In-situ preparation of InSb(111)thin films on Si(111)substrates with severely mismatched lattices and the growth mechanism of the thin film preparation process were investigated by molecular beam epitaxy,and related tests work were also conducted.On the basis of the Bi(001)film,we grew InSb(111)films under the appropriate growth conditions to obtain good crystal quality and smooth surface.The surface of the InSb(111)film is very smooth and has large size steps,and we have obtained InSb(111)-(2×2)reconstructed atomic resolution images.With the increase in InSb film thickness,the crystal quality gets higher and higher,and the quality of InSb film is further improved.At the same time,we also performed optical and Hall measurements for InSb films with variable thickness.The 300 nm InSb film mobility at300K was 1.7379×103cm~2/V·s.At last,after successfully obtaining high-quality InSb(111)thin films,the single polarity growth mode of InSb(111)thin films was further studied,and the morphology evolution of InSb thin films during epitaxial growth was also studied.By optimizing the growth mode,the obtained reconstructions of InSb(111)thin films are(2×6)and(2×2),which were obtained as the growth temperature increased,which proved that we obtained the InSb thin film as a single polar film.Also,as the growth temperature increases,the surface of the thin film changes from a three-dimensional island-like pattern(at room temperature)to a two-dimensional layered growth pattern.